5: Thermodynamic Potentials

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Page ID: 20406

Howard DeVoe
University of Maryland

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This chapter begins with a discussion of mathematical properties of the total differential of a dependent variable. Three extensive state functions with dimensions of energy are introduced: enthalpy, Helmholtz energy, and Gibbs energy. These functions, together with internal energy, are called thermodynamic potentials. (The term thermodynamic potential should not be confused with the chemical potential, $\mu$, to be introduced in Sec. 5.2.) Some formal mathematical manipulations of the four thermodynamic potentials are described that lead to expressions for heat capacities, surface work, and criteria for spontaneity in closed systems.

5.1: Total Differential of a Dependent Variable
A dependent variable is a function of the independent variables. The total differential of a dependent variable is an expression for the infinitesimal change of the variable in terms of the infinitesimal changes of the independent variables.
5.2: Total Differential of the Internal Energy
5.3: Enthalpy, Helmholtz Energy, and Gibbs Energy
5.4: Closed Systems
5.5: Open Systems
5.6: Expressions for Heat Capacity
5.7: Surface Work
5.8: Criteria for Spontaneity
5.9: Chapter 5 Problems

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